Flexible tank and method of making such a tank

Abstract

Provided is a flexible tank and method of making such a tank.

1 . A flexible tank that comprises a one piece body portion that is form using a blown film technique.  
   
   
       2 . A flexible tank as claimed in  claim 1 , wherein the one piece portion is a seamless tube.  
   
   
       3 . A flexible tank as claimed in  claim 1 , wherein the ends of the tube are closed, for example, by welding.  
   
   
       4 . A flexible tank as claimed in  claim 1 , wherein two one piece body portions are provided, one forming an inner liner and the other forming an outer liner.  
   
   
       5 . A flexible tank as claimed in  claim 1 , wherein the one piece body portion is made of polyethylene.  
   
   
       6 . A flexible tank as claimed in  claim 5 , wherein the one piece body portion is made of a polyethylene based resin and a bonding agent.  
   
   
       7 . A flexible tank as claimed in  claim 6 , wherein the ratio of resin to bonding agent is 75% to 25%.  
   
   
       8 . A flexible tank as claimed in  claim 6 , wherein the resin is Elite (Metallasin) 5100 resin (C6 Linear low density polyethylene (LLDPE)) made by Dow Chemicals.  
   
   
       9 . A flexible tank as claimed in  claim 6 , wherein the bonding agent is a co-polymer, preferably ethylene butyl acryiate (EBA).  
   
   
       10 . A flexible tank as claimed in  claim 1 , wherein the or each one piece body portion comprises two or more materials, preferably in layers, for example three or four.  
   
   
       11 . A flexible tank as claimed in  claim 10 , wherein a layer of the body portion comprises a flexible material.  
   
   
       12 . A flexible tank as claimed in  claim 11 , wherein the flexible material is polyethylene.  
   
   
       13 . A flexible tank as claimed in  claim 10 , wherein a layer of the body portion comprises a material that is adapted to reduce flex cracking.  
   
   
       14 . A flexible tank as claimed in  claim 10 , wherein the materials of the body portion are co-extruded during the blown film process.  
   
   
       15 . A flexible tank as claimed in  claim 10 , wherein the layers are made of different polyethylene, one being, for example, a linear low density polyethylene, the other being a low density polyethylene.  
   
   
       16 . A flexible tank as claimed in  claim 1  comprising an outer liner.  
   
   
       17 . A flexible tank as claimed in  claim 1 , wherein the material of the body portion has a thickness in the range of 100 to 250 μm, preferable 120-130 μm, preferably substantially 125 μm.  
   
   
       18 . A method of forming a flexible tank using blown film techniques to form a one-piece seamless body portion.  
   
   
       19 . A method as claimed in  claim 18 , wherein the one-piece seamless body portion is a tube.  
   
   
       20 . A method as claim in  claim 19 , comprising sealing the ends of the tube, for example, by welding.  
   
   
       21 . A method as claimed in  claim 18 , wherein the step of blowing the tube comprises co-extruding at least two layers of material to form the body portion.  
   
   
       22 . A method as claimed in  claim 18 , comprising forming a plurality of one piece body portions and fitting the body portions inside each other.  
   
   
       23 . A method as claimed in  claim 18 , wherein the one piece body portion is made of material that comprises a blend of resin and bonding agent.  
   
   
       24 . A method as claimed in  claim 23 , wherein the ratio of the resin to bonding agent is 75% to 25%.  
   
   
       25 . A method as claimed in  claim 23 , wherein the resin is Elite (Metallasin) 5100 resin (C6 LLDPE) made by Dow Chemicals.  
   
   
       26 . A method as claimed in  claim 18 , wherein the or each one piece body portion comprises two or more materials, preferably in layers, for example three or four.  
   
   
       27 . A method as claimed in  claim 26 , comprising forming a layer of the body portion using a flexible material.  
   
   
       28 . A method as claimed in  claim 27 , wherein the flexible material is polyethylene.  
   
   
       29 . A method as claimed in  claim 26 , comprising forming a layer of the body portion using a material that is adapted to reduce flex cracking.  
   
   
       30 . A method as claimed in  claim 26 , comprising co-extruding the plurality of materials of the body portion during the blown film process.  
   
   
       31 . A method as claimed in  claim 18 , comprising forming an outer liner and locating the body portion in the outer liner.  
   
   
       32 . A method as claimed in  claim 18 , comprising forming the body portion so that it has a thickness in the range of 100 to 250 μm, preferably 120-130 μm, preferably substantially 125 μm.